The invention relates to an acceleration sensor comprising:
a non-conducting, non-magnetic housing with a chamber which has a circular cross section in a first plane, PA1 an inductance influencing member which resides inside the chamber and has a circular cross section in the first plane, and PA1 a first coil which is inductively coupled to the inductance influencing member.
The invention further relates to a tracking device with such a sensor.
The invention further relates to a head mounted display with such a tracking device.
The invention further relates to a mouse with such a tracking device. An acceleration sensor of the above kind is described in a Dutch patent application, published under number 9300152. The known acceleration sensor has a spherical chamber with a ball of soft magnetic material. One or more coils are wound around the chamber, each enclosing the ball to a certain extent. In a certain orientation of the acceleration sensor, the coil or set of coils together with the enclosed ball have a certain self induction. When the orientation changes, the ball moves inside the chamber under the influence of the field of gravity and the self induction changes. This change is detected and used as a trigger in an alarm system. A product can thus be protected against theft by fixing such an acceleration sensor to the product. The known acceleration sensor only detects whether a change of orientation takes place, without qualifying the amount of change, and is incapable of determining the direction of the change.